A herringbone land drainage system is one of the most efficient ways to remove excess water from lawns, gardens, and small fields, especially in areas with persistent waterlogging. It uses a central collector drain with angled lateral pipes arranged like a fishbone, allowing water to be captured from multiple directions and channelled toward a soakaway or outlet.

The CivilWeb Field Drain Design Spreadsheet can be used to accurately and quickly design all kinds of field drains.

🌿 Why Herringbone Drainage Works Well

A herringbone layout is designed to maximise water interception across a wide area. The central pipe runs along the lowest point of the site, while lateral pipes feed into it at angles. This pattern ensures that water is collected evenly, even on irregular or sloped ground. It is particularly useful in the UK, where high rainfall and clay soils often lead to saturated lawns and gardens.

Key advantages include:

• Efficient collection of water from multiple directions.
• Ideal for medium-sized lawns and landscaped areas.
• Works well in clay or poorly draining soils.
• Reduces waterlogging that can damage plants, turf, and foundations.

🧱 Components of a Herringbone Land Drainage System

A typical system includes:

• **Main collector drain** — laid along the natural fall of the land.
• **Lateral drains** — smaller perforated pipes feeding into the main drain at angles.
• **Perforated drainage pipe** — usually 80mm for domestic gardens.
• **Geotextile filter socks or wrap** — prevents silt from entering the pipe.
• **Clean angular stone** — surrounds the pipe to promote flow and prevent clogging.

Some commercial kits are designed specifically for herringbone layouts, such as 80mm garden drainage packs that include perforated pipe, Y‑junctions, end caps, and geotextile socks. These can drain areas up to around 240m².

📐 How to Design a Herringbone Drainage System

1. Assess the Site

Identify the lowest point of the garden and the direction of natural water flow. This determines the position of the main drain.

2. Set the Main Drain

Install the main pipe along the lowest line of the site with a gentle fall toward the outfall. A typical gradient is 1:100 to 1:200.

3. Add Lateral Drains

Install lateral pipes at 45° angles feeding into the main drain. Spacing depends on soil type:

• Clay soils: closer spacing for better capture.
• Sandy soils: wider spacing is acceptable.

4. Use Proper Backfill

Surround pipes with clean stone and wrap with geotextile to prevent siltation.

5. Provide a Suitable Outfall

Direct water to:

• A soakaway,
• A watercourse or swale,
• A surface water drain (with permission).

🌧️ When to Choose a Herringbone System

This layout is ideal when:

• The garden suffers from widespread waterlogging.
• Water needs to be collected from multiple directions.
• The area is too large for a single linear drain.
• The soil is dense or clay-based, causing slow infiltration.

It is less suitable for:

• Very small areas (a single linear drain may suffice).
• Sites with no viable outfall.
• Areas where tree roots may interfere with pipework.

🛠️ Installation Tips

• Keep the main drain on the natural fall of the land.
• Ensure all lateral pipes connect at consistent angles.
• Avoid sharp bends that may trap silt.
• Use junctions rather than forcing pipes to bend.
• Install inspection points where practical for maintenance.

💷 Cost Considerations

Costs vary depending on depth, soil type, and access, but herringbone systems are generally cost‑effective for medium‑sized gardens. Pre‑packaged kits can simplify installation and reduce waste by providing the correct pipe sizes and fittings.

🌱 Final Thoughts

A herringbone land drainage system is a reliable, efficient, and time‑tested method for dealing with waterlogged ground. Its fishbone layout ensures even water capture, making it ideal for UK gardens with clay soils or poor natural drainage. With proper design, installation, and a suitable outfall, it can transform a soggy lawn into a usable, healthy landscape.

The CivilWeb Field Drain Design Spreadsheet can be used to accurately and quickly design all kinds of field drains.